# Max Const. Deceleration

1. Aug 21, 2013

### sandman203

1. The problem statement, all variables and given/known data

Hi all this is just a quickie, but in one of my texts a question asks to find the maximum constant deceleration given an initial speed, time to stop and the distance it took.

Now im not sure whether to use v = u + at or s = 1/2at^2 + ut

im thinking more v = u + at becuase im not given displacement, im given a distance.. any thoughts? cheers!

2. Aug 21, 2013

### CWatters

Do both give the same answer?

3. Aug 21, 2013

### rcgldr

If it's constant acceleration, and the given inputs are the initial speed and time to stop, there there is only one possible constant acceleration (deceleration). The maximum and minimum would be the same. I'm not sure why that was mentioned. It the distance to stop is also given, it either corresponds to the time, or else there's a conflict in the problem statement.

4. Aug 21, 2013

### SteamKing

Staff Emeritus
Why would you think, in this case, that displacement is not equal to distance?